1. Field of the Invention
This invention relates generally to devices for permitting access to the interior of existing sight-glass devices as in use on the sides of tanks and other vessels. The reason being to permit ready and easy access to the interior of the sight glass for the purpose of cleaning same.
2. Description of the Prior Art
A common problem with known sight-glass devices is that the arrangement of same is such that ready access to the interior of the sight glass is not achievable. In order to clean a dirty or rust contaminated sight glass, it is necessary to remove one or both ends of same from the existing supporting valve structure, which often results in breakage of the glass from which the sight-glass is made.
Another problem with known type construction of sight glasses is that the valve arrangement does not permit easy disengagement of the sight glass therefrom for the purpose of cleaning and replacement of same.
Known prior art patents which may be pertinent to this invention are as follows: U.S. Pat. Nos. 311,471; 1,294,568; 2,333,397; 763,300; 1,460,873; 3,174,338.
None of these prior art devices offers the new and unique features of the invention disclosed herein.